U.S. Pat. No. 4,369,243 Credner e.a., Jan. 18, 1983, shows in a silver halide photographic system the reductive cleavage of a "tailed" sulfilimine dye derivative to release a diffusible dye in the non-exposed areas. However, this patent does not show the particular dye structures here of interest nor that the cleavage of the sulfilimine bond with the proper dye structure can be effected by heat alone with the rendering of the dye irreversibly colorless in the heated areas.
U.S. Pat. No. 4,405,788, Locatell e.a., Sept. 20, 1983, shows related xanthene dye structures in photographic systems but does not show ylides.